Saalam alaikum
the longer we keep our mouth sut, the better we'll be.
but if your mouth speaks up good things, useful things and conducts your necessary duties like serving family, teaching students...so whats the problem??
I thing if keeping silence/full mute keeps away from your necessary duties then it is not permissible. I thing so. It is nowhere instructed that you have to forget everything, ahve to keep mute and do pray to Allah azza wa jal. if it was permissible then prophet salla Allahu alaihi wa sallam surely have done this, because he had the most concentration towards Allah azza wa jal.
beleive me sister, may be my reply seems like harsh, but I'm just writing it with a smile on my face. may be my clear cut answer made this little harsh.
I'm also not free from this type of confusions... he he...sometimes i think that I should not speak, otherwise it will bark...lolz.....he he...and sometimes it really barks....then i think,,,ohho, it would be better to have silence.
I think you were very clear to your statement and so you posted this. but there is no such FASTING, I guess.
try to remain silent most of the time, dont talk idle things, dont listen to music coz it lets the mouth to sing idle talks, dont gossip for hours over phone or direct, coz the moe time you will forget Allah azza wa jal, the Satan will more have the chance to flow into the idle talk, may be that can lead to back-biting, coz satan loves to make you eat the meat of your dead brother....and surely he will not loose the chance.
whenever you get time, recite from Quran, make dua, Dhikr, inshaa'Allah you and your mouth will be fresh. i try these, you can try, may be these gonna work..inshaa'Allah...aaaa to make yourself indulge in the Dhikr and recitation, read the Quran with meaning and tafseer. or you can read Hadeeth, beleive me you will not find the time going...
may Allah subhanahu wa ta'la save us from bidah and shirk
may Allah ta'la protect our eeman and health
wassalamu alaikum